fornaca



Feb. 28, 1928.

INTERNAL coMBUsTIoN `ENGINE FoRNAcA Filed Dec. 23. 1924 x 0.5516511440? lll. v

f flnn. (255,521.2,

* page EN.' l.

aureo scannen, er aniram, ITALY.

DTTERNAL-COMBUSTION ENGINE.

Application filed December 23, 1924, Serial No. 357,682, and in Italy December 31, 1923.

Inthe operation of internal combustion engi/nes of the usual type (low compression and electric ignition). on heavy fuel, the mixture is generally pre-heated by causing the exhaust gases to circulate around the 1nlet pipe and thus produce vaporization of the fuel previously sprayed by the carburetn ter.

It has been found in practice that such engines operating on heavy fuel are far 'from flexible and present many disadvantages in operation due to the fact that sometimes the mixture is insuticiently heated and burns badly, leaving a carbon residue which settles on the sparking plugs and valves and gives rise to irregular runnlng and even to stoppage of the engine; and sometimes, especially in prolonged operation and during hot weather, the heating is'excessive and the engine gives a low eficiency and is subject to prema ture ignition which seriously imperils the strength of the parts and also causes irregular running which may make it necessary to stop the engine.

For this reason it has already been proposed to provide. a double inlet pipe one branch oil which `is adapted to be heated by the exhaust gases, together with a valve whereby the combustible mixture can be directed through either branch. It has also been proposed to provide means whereby the intensity'of heating of the mixture can be regulated, either by hand or automatically by thermostatic action, during the actual running of the engine to suit the require` ments and conditions of the engine. y

The object of the present invention is fto provide means whereby the intensity of heating of the mixture can be regulated in a perfectly rational way and during the actual running `of the engine to suit the requirements. and conditions of the engine. Said means comprise a double inlet pipe, one branch of which is arranged to be traversed externally preferably over its entire length 'by the products of combustion, while the other branch is arranged to be heated only over a portion of its length, and a valve by which the aseous mixture canv be directed through eit er of said branches or through both as required to obtain the proper amount Y of heatin The vave may be operated by hand or by an automatic arrangement controlled b fthe temperature of the inlet gases measure ata point near the inlet valve.

rPhe appended drawing shows two exam ples of the invention.

F ig. 1 is an elevation (partly in section) of an internal combustion engine embodying one form of the invention.

Fig. 2 is a similar view of a modified form including an automatic control device for the aforesaid valve.

In the drawing, the reference l denotes the engine from the carburetter 2 of which leads a double inlet pipe having branches 3 and 3** which join at 4 near the inlet valve 5. The branch 3 is jacketed over the greater portion of its length by a casingwhich has the double function of a mixture heater and muffler for the waste gases, discharged from the'cylinder past the valve 7. This branch 3 formsan annular chamber in the casing tand as it extends across and in front of the exhaust port of the engine it constitutes a baille for4 the exhaust gases issuing from said port and at the same ltime operates to distribute said gases in the lannular chamber. The branch 3a, however, is traversed externally by the exhaust gases only 'over a short length so that the heating. to which it is subjected is much 'less intense. As the upper end of branch 3a passes through the upper-part of casing 6 it also constitutes a baille for the exhaust gases in the'annular chamber and operates to retard the movement of the gases from the latter to the exhaust ort of the casing. The inlet port in the si e of casing 6 is arranged substantially between the ends of the 'annularchamber'so that the gases from the exhaust port of the engine in meeting the first baille or branch 3 expands towards both ends of said chamber and as the movement of the gases towards the exhaust port ofthe casing 6 is retarded by the second baille or branch 3a both an efecting heating of the branch 3 and an effective retarding of the gases are obtained.

At the lower inaction of the branches 3 and 3* is arranged a valve 8 which allows the aseous mixture to be directed into either of te branches or into both in dierent proportions in order to pre-heat it to the re-l quired degree. 0n starting the engine, when the carburetter is fed with petrol, the valve 8 is set to direct the gaseous mixture through the branch 3, no heating being necessary at this sta e.

en changing over from petrol to heav fuel (naphtha) the valve 8 is set in 'suoli manner that the gaseous mixture passes entirely through the branch 3 in order to obtain the most intense heating.

As soon as the engine is hot enough a part of the gaseous mixture is directed along the branch 3a, thus reducing the ytotal heating to a variable extent to suit the engine conditions and the external temperature.

In order to 'countenbalance its progressive heating` during the continued operation of the engine, gradual reduction is made of the quantity of gaseous mixture passing' through the branch 3 and during hot weather said branch may be closed com letely.

The valve 8 may be operated y hand in any convenient manner, or if it is desired to save the drivertrouble there may be provided a` suitable automatic control, an example of which is shown in Fig. 2.

In this case a thermostat 10 is arranged in the inlet pipe at the upper junction 4 of the branches 3, 3a, the same being .capable of expanding appreciably under the action of l heat and being connected, by a rod 11, to a lever 12 Whose other arm is coupled, by a link 13, with a lever 14 fixed on the spindle of the valve 8. l

It is evident that the position of the valve 8 depends in this case on the temperature of the place in which the'thermostat 10 is situated and that an increase of temperature will cause a displacement of the valve 8 in a direction to choke the branch 3. The result is easily obtained, therefore, of a constant temperature of the gaseous mixture passedA into the cylinder independently o f' the outside'temperature and the temperature conditions of the engine.

VYhat I claimis:

The combination with a combustion engine having inlet and'exhau'st ports arranged one above the other on the same side of the engine, and a carburetter disposed below said ports, of a casing, constituting a mixture heater and muffler, having a port on one side communicating with the exhaust port of the engine and an exhaust port communicating with the atmosphere, a conduit connecting the -carburetter with the inlet port of the engine and having a bifurcated portion between its ends, one branch of the ifu-rcated portion extending substantially throughout its length through the casing and forming an annular chamber therein, said branch passing in front of the engine exhaust port, constituting a baffle for the gases issuing from the latter and thereby distributing said gases in the annular chamber, the other branch of the bifurcated portion of the conduit having its upper portion passing" through the upper part of the casing and communicating with the first named branch at-the upper end of the latter, and constituting a baille for the exhaust gases in the annular chamber between the latter and the exhaust port of the casing, `and a by-pass va'lve arranged at the bifurcation point adjacent the carburetter. l

In testimony that I claim the lforegoing as my invention, I have signed my name.

GUIDO FORNACA. 

